Field
Exemplary embodiments of the present disclosure relate to an apparatus and a method for equalizing a channel and determining reception data in a packet communication receiver.
Description of the Related Art
In a packet transmission method which uses π/4-DQPSK which is one of differential modulation methods, as a modulation method and has a binary data string called midamble in the middle of the packet, a binary data string of the midamble is a data string which is determined in advance between a transmitter and a receiver. The binary data string is mapped and transmitted as a symbol in accordance with the π/4-DQPSK modulation method in the transmitter. The π/4-DQPSK modulation method is one of differential modulation methods and determines a signal to be transmitted for every packet by a transmission data string.
In the transmitter, a π/4-DQPSK modulation symbol string is transmitted and then passes through a channel to reach the receiver. The receiver may include a channel equalizer to compensate distortion generated in the channel. The receiver has a receiver structure which differentially demodulates an output signal of the channel equalizer to determine transmitted data.
Generally, when an adaptive channel equalizer is used, the equalizer is trained using known symbol strings and corresponding reception signals. The trained equalizer uses reception data to perform channel equalization.
However, when the midamble is used, a symbol string which may be used to train the equalizer is located in the middle of a packet. Therefore, it is difficult to apply a general adaptive channel equalizer algorithm. Further, as mentioned above, due to a characteristic of the π/4-DQPSK modulation method, midamble symbol strings by the midamble binary data vary for every packet due to the different packet data, so that it is difficult to apply a typical channel equalizer.
The related art is disclosed in Korean Unexamined Patent Application Publication No. 10-2008-0050244 (entitled Apparatus and method for channel equalizing using absolute value of Channel Coefficient and published on Jun. 5, 2008).